Circuit Description
The steering wheel position sensor produces 2 separate voltage signals to indicate steering wheel position to the real time damping (RTD) module. The RTD module converts each signal into a pulse width modulated (PWM) signal to indicate steering wheel position to the EBCM. The EBCM supplies 5 volts to the RTD module on each steering wheel position PWM serial data circuit. The RTD module toggles each of these voltages to ground in order to create the PWM signals. Each PWM signal must have a frequency of 121-134 Hz and a duty cycle of 9-91 percent in order to be a valid steering wheel position signal. With each 360 degree rotation of the steering wheel, each signal transitions from the minimum duty cycle to the maximum duty cycle and then back to the minimum duty cycle. The steering wheel position signals are spaced 90 degrees apart. Therefore, the duty cycles of the 2 signals usually differ, depending on steering wheel position.
Conditions for Running the DTC
C0205, C0206 and C0207
The ignition is ON.
C0208
The vehicle is driven straight forward at a speed greater than 19 km/h (12 mph) for more than 20 seconds.
Conditions for Setting the DTC
C0205
At least one of the steering wheel position PWM signals is out of range for 500 milliseconds.
C0206
The steering wheel position PWM signals indicate a sudden change in the steering wheel position which exceeds a physical limitation.
C0207
The steering wheel position PWM signals do not correlate with each other for 200 milliseconds.
C0208
The steering wheel position that is indicated while driving the vehicle straight forward is at least 20 degrees greater or less than the steering wheel position that was indicated during the sensor initialization period.
Action Taken When the DTC Sets
| • | The EBCM disables the VSES. |
| • | The message center displays the SERVICE STABILITY SYSTEM message. |
Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.
Diagnostic Aids
Important: A malfunction between the steering wheel position sensor and the RTD module may be responsible for setting this DTC. When attempting to verify an intermittent malfunction, be sure to use the scan tool to send the Clear DTCs command to the RTD module. This enhances the RTD module's diagnostic capabilities so that the RTD module sets DTCs more readily. Do not cycle the ignition after sending the Clear DTCs command. Test drive the vehicle, making several turning maneuvers in both directions. If the service stability message is displayed due to DTC C0205, C0206, C0207 or C0208, use the scan tool to inspect for Current or History RTD DTCs. If the RTD module has set DTC C0470, C0506, C0521 or C0895, refer to the DTC list in Variable Effort Steering for diagnosis. If the RTD module has set DTC C0550, C0551 or C0870, refer to the DTC list in Real Time Damping for diagnosis.
| • | Inspect the vehicle for bent, worn or loose steering or suspension components. |
| • | Inspect the vehicle for proper wheel alignment. The vehicle should not pull toward the left or right while driving straight forward on a level surface. |
| • | Use the Snapshot function on the scan tool in order to assist you in locating an intermittent malfunction. |
| • | Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Electrical Intermittents , Testing for Intermittent Conditions and Poor Connections , Wiring Repairs and Connector Repairs in Wiring Systems. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if there is a problem between the steering wheel position sensor and the RTD module.
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This step tests for voltages supplied to the RTD module from the EBCM. A short to voltage is indicated if voltage on either circuit measures greater than 5.25 volts.
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This step tests each steering wheel position PWM signal for a valid Hz frequency. Each measurement is made by backprobing one steering wheel position PWM signal circuit at the RTD module harness connector with one DMM lead and connecting the other DMM lead to a good ground.
-
This step tests each steering wheel position PWM signal for a valid duty cycle.
-
The RTD module may be damaged if either of the steering wheel position PWM serial data circuits is shorted to voltage.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics | ||||
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the DTC reset? | -- | Go to Step 3 | Go to Diagnostic Aids |
|
Important: Before proceeding with this diagnostic table, you must determine if a malfunction exists in the steering position signal input to the RTD module. Carefully perform the steps below to determine which diagnostic table you should continue using.
Important: Perform the action below even if no RTD DTCs are set. Sending the Clear DTCs command to the RTD module enhances the module's diagnostic capability, and allows the RTD module to set DTCs more readily. Does the RTD module set DTC C0470, C0506, C0521 or C0895? | -- | Go to Diagnostic Trouble Code (DTC) List in Variable Effort Steering | Go to Step 4 | |
4 | Does the RTD module set DTC C0550, C0551, or C0870 during step 3? | -- | Go to Diagnostic Trouble Code (DTC) List in Real Time Damping | Go to Step 5 |
Do both voltages measure within the specified range? | 4.75 V-5.25 V | Go to Step 7 | Go to Step 6 | |
6 | Test the suspect steering wheel position PWM serial data circuit for an open, a short to ground or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 9 |
Do the frequencies of both steering wheel position signals measure within the specified range? | 121-134 Hz | Go to Step 8 | Go to Step 11 | |
Use the DMM in order to measure the duty cycle of each steering wheel position PWM signal, one at a time. Do the duty cycles of both steering wheel position signals measure within the specified range? | 9-91 % | Go to Step 10 | Go to Step 11 | |
9 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
10 |
Important: Following EBCM replacement, use the scan tool to perform the Tire Size Calibration procedure. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
Test the suspect steering wheel position PWM serial data circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 | |
12 | Inspect for poor connections at the harness connector of the RTD module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 |
13 |
Important: Perform the set up procedure for the RTD module. Replace the RTD module. Refer to Electronic Suspension Control Module Replacement in Real Time Dampening. Did you complete the replacement? | -- | Go to Step 14 | -- |
14 |
Does the DTC reset? | -- | Go to Step 3 | System OK |
